Alkylation of paraffin hydrocarbons



Patented Mar. 9, 1943 YLATION OF PARAFFIN HYDN S Charles L. Thomas,Chicago, Ill., assignor to Universal Oil Products Company, Chicago,111., a corporation of Delaware I No Drawing. Application March 25,1939,

- ScriaiNo.264,117

'8 Claim.- (01. 196-10) This invention relates particularly to thetreatment of 150 or branched chain paramn hydrocarbons.

In a more specific sense the invention is con-' cerned with a novelprocess for alkylating iso or branched chainparafiin hydrocarbons witholefinic hydrocarbons to produce saturated hydrocarbons of highermolecular weight which can be utilized as constituents of motor fuel.

The cracking process which is operated principally with the object ofproducing gasoline from heavier and less valuable petroleum fractionsincidentally produces considerable yields of fixed gases consisting. ofhydrogen, methane, ethane,

propane, and butanes, as well as ethylene, propene, and butenes invaryin quantities and proportions. In most instances, these gases areconsidered to be valuable merely as fuel, although attempts have beenmade from time to time to utilize the oleflnic constituents for themanufacture oi hydrocarbon derivatives, on a commercial basis.

In one application of the present process the I isobutane and olefinspresent in cracked gas mixtures are utilized as a source of additionalyields of motor fuel fractions to augment those produced primarily bycracking. While the process is applicable to the utilization of thehydrocarbons in cracked gas mixtures and particularly selected fractionsproduced therefrom in the sta-. bilizers' of cracking plants, it is alsoapplicable to the treatment of iso or branched chain parafused ascatalyst in the process of this invention,"

consists in treating fiuorospar (Cam) with fum ing sulfuric acid (50-60%50:). It is a mobile liquid with a boiling point of 163 C. and a faintpungent odor but with substantially no harmful action on dry skin. Itfeels greasy to-the touch and is without the intense blistering actionof anhydrous hydrogen fluoride.

The total reactions occurring when an isoparaf fin is alkylated with anolefin in the presence of. fiuorosulfonic acid will necessarily involve,to

some extent, not only simple alkylation corresponding to the addition ofone or more molecules of the olefin to an isoparafiln, but also somereactions of polymerization and some decomposition so that the netresult is the production of amixture of hydrocarbons having aconsiderable boiling range, but containing a. large proportion oimono-alkylated products.. The reactions of polymerization are usually ofa negligible order when a moderate excess of isoparaiiln is present inthe reaction zone.

In operating the process of the present invention the preferredprocedure is to agitate a mixture of fluorosulfonic acid and anisoparamn and introduce gradually a mixture of an olefin and anisoparaflin below the surface of the mixture or acid and isoparafiinwhile the reaction mixture is under a pressure sufiicient to keep asubstantial proportion of the reactants in liquid phase. A

temperature range of approximately 0-100 C.

fins and olefins produced from any other source. I

Eilorts to alkylate normal paraffln hydrocarbons.

with olefins in the presence of catalysts have thus far failed unlessconcurrent isomerization of the normal to branched chain paramn occurs.Isobutane, however, may be made to interact with olefins to producesaturated products, and with butenes, particularly isobutene, in thepresence of various catalysts to form branched chainoctanes commonlyreferred'to as iso-octanes.

In one specific embodiment the present invention comprises a process foralkylating is'oparafiln hydrocarbons with mono-olefinic hydrocar-- bonein the, presence of fluorosulfonic acid as catalyst.

Whereas previous work in alkylating various classes of hydrocarbons witholefins has indicated that the reactions can be brought about in thepresence ofboron fluoride and minor amounts of hydrogen fluoride, thesereaction are better effected' when using fluorosulfonic acid ascatalyst. During such alkyiation reactions the maintenance of an excessofisoparamn minimizes polymerization so that the products consist main-1y of higher boiling isoparafilns formed by the and a pressure-range ofthe order of 2-20 atmospheres has been found suitable in the alkylationof the lower boiling isoparaflins as isobutane and i'sopentanebynormallv gaseous olefins, but these operating conditions may bealtered for effecting similar reactions between higher boiling parafiinsand olefins of varied structures.

In batch operation oi this process the-agitation may be stopped vand'theupperhydrocarbon layer removed and fractionated to recover the unchangedparaillns and the desir'ed'alkylated products. Continuous operation ofthe process may reaction of the oleflnic hydrocarbons with the isocharged.

One method of preparing iiuorosulfomc acid,

be made by providing a mixing zone in which the iso'paraflin, olefin,and acid catalyst are contact ed for a suiiicient time to efiect thecompletion of the desired alkylation. reactions, after which the mixtureis separated in a settling zone from which the hydrocarbon layer may bewithdrawn and fractionated to separatethe desired products and torecover unconverted parafiln for recycling. From this settling zone thelower layer, consisting or the fluorosulfonic acid catalyst is pumpedback to the reaction zone for further service.

In case a considerable portion of the alkylation product boils higherthan the end point of commercial gasoline, iractionating of thishydrocarbon material may be made in two stages,

the first stage, removing the uncombined 4-car-' bon atom hydrocarbonsand being in effect a sta- 7 and 162 parts by weight of isobutene wascontacted with 100 parts by weight of fluorosulfonic acid during twohours at a temperature of 15 C. under a pressure which varied between3.5 and 4.5 atmospheres. After the reaction 220 parts -by weight of aliquid hydrocarbon product was recovered equivalent. to 135% by weightof the olefln charged to the reaction. This hydrocar- The process of thepresent invention may be utilized successfully to produce octanes whichare largely of an isomeric character from the mixtures of i-carbon atomhydrocarbons which are obtainable either by the dehydrogenation ofbutanes, the close fractionation of cracked gasv mixture suchas thoseproduced as overhead from cracking plant stabilizers, or by utilizing asecondary cut of the overhead from the stabilizers which consistprincipally of the desired i-carbon atom hydrocarbons, includingisobutene, normal butenes, isobutane, and normal butane.

, In the treatment of such hydrocarbon mixtures with an alkylationcatalyst, such as fluorosuli'onic acid, the primary reactions involveprincipally the interaction of the isoparafllns with the olefins.Obviously the above procedure-for utilizing the isobutane and butenes in4-carbon atom hydrocarbon fractions, can be followed only when there isa suflicient amount of isobutane to react with both the isobutene andn-butenes present. The process of the present invention, if desired, maybe carried out on isobutane and n-butenes separated by fractionation andsolvent extraction methods from 4-carbon atom hydrocarbon fractions. theoleflns may be concentrated by their preferential solubility in varioustypes of hydrocar- For example,

bon and other solvents,'and the olefin concen-- trate fractionated tosubstantially separate isobutene from n-butenes. Similarly, isobutaneand n-butane may be separated by the fractionation of the rafllnate. Forthe proper functioning of a process of the present character itis'usually advisable to employ these preliminary separation methods tobe able to proportion the isobutane and butenes to avoid any tendencyforpolvmerization reactions to occur. I

In the presence of an excess 0 f isobutane, one

bon product consistedes'sentially of paraflinic hydrocarbons, 90%byvolume thereof being in the gasoline boiling range, of which a totalof 60% by volume was aviation gasoline with a a boiling range of from to150 0., and included approximately 27%.of iso octanes, 18% iso nonanes.7

Example 11 Isobutane and 'fluorosuli'onic acid were sure, and propene,in less than equivalent amount run in, the temperature then beingmaintained at about 25 C. and the pressure approximately 10 atmospheres.liquid product was thereafter separated by decantation from thecatalyst, washed with water". and dried, and found to be essentiallyiso-v heptanes. v

The character of the process of the present invention, and particularlyits commercial value, are evident from the preceding specification anddata presented, although neither section is intended to unduly limit itsgenerally broad scope.

"I claim as my invention:

1. A process for synthesizing hydrocarbons which comprises alkylating anisoparafiln with an olefln in the presence of fluorosulfonic acid.

. ,2. A process for producing liquid hydrocarbons from hydrocarbon gaseswhich comprises alkylating a normally gaseous isoparaflin with anormally gaseous olefin in the presence of 'fiuorosulfonic acid.

- 3. A process for producing hydrocarbons boiling in the gasoline rangewhich comprises alkylatingisobutane with a normally gaseous olefin inthe presence of fluorosulfonic acid.

.4. A process for producing octanes which comprises alkylating isobutanewith a butane in the presence of fluorosulfonic acid.

"molecular equivalent of n-butene tends to react withits molecularequivalent of isobutane while the excess of'isobutane remainsunaffected.

When more butene is used than corresponds to about one mole to two molesof isobutane, there is an increased tendency for polymerizationreactionsto occur in preference to alkylation reactions. This is to be expectedto some extent on account of the readiness with which butenes alone arepolymerized byacid catalysts. How

ever, by maintaining the proper excess of isoparafiin hydrocarbon thecourse of-the reactions may be kept principally in the direction ofproduction of alkylated products of a saturated rather than an oleflniccharacter. Besides the primary reaction of an isoparaflin with an olefinthere is alsosome production of higher boil-- .ing products due to thereaction of one molecule of an isoparaflin with two-molecules ofanolefln forming a dialkylated paraflin.

The following examples are given to indicate typical results obtainablein the operation of the process, although not with the intention ofunduly limiting the scope of the invention.

Eatample I A mixture of 180 parts by weight of isobutane 5. A processfor, converting normally gaseous into normally liquid hydrocarbons whichcomprises alkylating a normally gaseous isoparamn with a normallygaseous mono-olefin in the presence of fluorosulfonic acid, whilemaintaining a substantial portion of thesaid reactants in the liquidphase.

6. A'process for producing octanes which com prises alkylating isobutanewith isobutene in the presence of fluorosulfonic acid at a temperatureof the approximate order of 0-100? 0. under a pressure in theapproximate range of 2-20 atmospheres.

'7. A process for producing octanes which comprises alkylating isobutanewith normal butenes in the'presence of fluorosuifonic acid at atemperature of the approximate order of 0-100 C.

under a pressure in the approximate range of 2-20 atmospheres. p

' 8. A process for producing heptanes which comprises alkylatingisobutane with propene in the presence of fluorosulfonic acid at atemperl ature of the approximate order of 0-100 C.

under a pressure in the'approximate range of 2-20 atmospheres. Y

L'. THOMAS.

. agltated at room temperature and elevated pres- The resultantCERTIFICATE OF cdRREcTIoN. Patent No. 2,315,105. March 9, 1915.

cmmmss L. THOMAS.

It is hereby certifed that error appears in the printed specification ofthe above numbered p atent requiring correction as follows: Page 2,sec-- 0nd column, line 1 .6, claim 14., for 'bntane read --bu tene--';and that the said Letters Patent should be read with this correctiontherein that the I same may conform to the record of the case in thePatent Office. I

Signed and sealed this 26th day of October, A. D. 1915.

, Henry Van Arsdale,.

(Seal) v v Acting Commissioner of Patents.

